Thursday, October 21, 2010

Fainting is a symptom of an inadequate supply of oxygen and othernutrients to the brain, usually caused by a temporary decrease in bloodflow. Blood flow to the brain can decrease whenever the body cannotquickly compensate for a fall in blood pressure.

Causes

1. Fainting may occur if the heart cannot pump enough blood to maintain anormal blood pressure. For example, an abnormal heart rhythm or a heartvalve disorder may impair the heart's pumping ability. People with suchdisorders may feel fine when resting. However, they feel faint or actuallyfaint when exercising because the heart cannot pump enough blood to meetthe body's increased demand for oxygen. This type of fainting is calledexertional or effort syncope. People with these disorders may also faintafter exercising. During exercise, the increase in heart rate may enablethe heart to pump enough blood to maintain adequate blood pressure,although just barely. When exercise stops, the heart rate (and the amountof blood pumped) begins to decrease. However, the blood vessels inmuscles, which dilate (widen) during exercise to move more blood to andfrom the muscles, remain dilated. (The arterioles in muscles remaindilated to help supply oxygen and nutrients to muscle tissue, and theveins remain dilated to remove metabolic waste products produced duringexercise.) The decrease in the amount of blood pumped out combined withdilation of the arterioles and veins causes blood pressure to fall, andfainting results.

2. An abnormality of the heart called hypertrophic cardiomyopathy (seeCardiomyopathy: Hypertrophic Cardiomyopathy) can also cause fainting thatusually occurs during exercise. This disorder may occur in younger peopleas well as older people, particularly those who have high blood pressure.If untreated, it can lead to death.

3. Fainting may occur if blood volume is too low. An obvious cause of lowblood volume is bleeding. Another cause is dehydration, which may be dueto diarrhea, excessive sweating, inadequate intake of fluids, or excessiveurination (which is a common symptom of untreated diabetes (see DiabetesMellitus) or Addison's disease (see Adrenal Gland Disorders: Addison'sDisease)). In older people, the use of diuretics is a common cause ofdehydration, particularly during warm weather or during an illness whenobtaining or drinking enough fluids may be difficult. (Diuretics help thekidneys eliminate salt and water by increasing urine formation and thusdecrease fluid volume in the body.)

4. Fainting may occur if the vagus nerve, which supplies the neck, chest,and intestine, is stimulated. When stimulated, the vagus nerve slows theheart. Such stimulation also causes nausea and cool, clammy skin. Thistype of fainting is called vasovagal (vasomotor) syncope. The vagus nerveis stimulated by pain (such as intestinal cramps), fear, other distress(such as that due to the sight of blood), vomiting, a large bowelmovement, and urination. Fainting during or immediately after urination iscalled micturition syncope. Rarely, vigorous swallowing causes faintingdue to stimulation of the vagus nerve.

5. Fainting may also occur if straining reduces the amount of bloodflowing back to the heart. Fainting due to coughing (cough syncope)usually results from such straining. Fainting after urination (micturitionsyncope) or after a bowel movement is partly due to straining (in additionto stimulation of the vagus nerve). Older men who must strain to emptytheir bladder because of a large prostate gland are particularlysusceptible. Fainting when lifting weights (weight lifter's syncope)results from the strain of trying to lift or push heavy weights withoutbreathing adequately during the exercise.

6. Fainting that occurs when a person sits or stands up too quickly iscalled orthostatic (postural) syncope. It is particularly common amongolder people. It is caused by orthostatic hypotension (see Low BloodPressure: Orthostatic Hypotension). In orthostatic hypotension, thecompensatory mechanisms, particularly the constriction of blood vesselsand the increase in heart rate, do not adequately restore blood pressurewhen a person stands and gravity causes blood to pool in the leg veins. Arelated form of fainting, called parade ground syncope, occurs when peoplestand still for a long time on a hot day. If the leg muscles are not used,blood is not pumped back to the heart. As a result, blood pools in the legveins, and blood pressure falls.

8. Fainting may result from very rapid breathing (overbreathing, orhyperventilation), which may be due to anxiety. This type of fainting iscalled hyperventilation syncope. Overbreathing removes large amounts ofcarbon dioxide from the body. The decreased level of carbon dioxide causesblood vessels in the brain to constrict, and the person may feel faint oractually faint.

9. Rarely, fainting results from a mild stroke in which blood flow to apart of the brain suddenly decreases. Fainting due to a stroke is morecommon among older people. Many other disorders, such as a deficiency ofred blood cells (anemia), lung disorders, a decreased blood sugar level(hypoglycemia), and diabetes can cause fainting, especially if thecompensatory mechanisms are also impaired.

10. Certain drugs may cause fainting. They include many of those used totreat high blood pressure, angina, and heart failure. Doses of these drugsmust be carefully adjusted to prevent blood pressure from decreasing toomuch.

Tuesday, October 19, 2010

Run for A Ray of Hope, is part of the Health Fiesta which is organised by the medical students of the National University of Malaysia (UKM). The purpose of this Charity Run is to raise funds for patients who are in need of financial support for their treatment in PPUKM, Cheras.

In conjunction with the run, there will also be a health campaign which will be held from 13 - 14 November, with booths available for free health screening, health education, health talk and health consultation. Several NGOs (such as Federation of Reproductive Health Associations, Malaysia, Pink Triangle Foundation, Malaysians AIDS Council and National Cancer Society Malaysia) will be giving health education on that day.Besides, Pusat Darah Negara is welcoming everyone to donate blood on the day of event.

Entry Fee

Open: RM 25

School: RM 15 each participant

UKM Student: FREE

* Only First 500 people will be able to get the Dry-fit jersey (excluding UKM student).

* All profits will go to SAHABAT PPUKM for the needy patients in UKM Medical Centre